Each hub can support up to five transmitters, and each transmitter can support up to three CT clamps.

Each transmitter equates to one line on the graph of your usage that Efergy tracks; the "the bottom line" of one data stream of energy use.

Most U.S. residences have two incoming 110 volt lines, for 220 volts total. These would need two CT clamps, which is why the introductory hub package comes with two CT clamps. Other circuits only need one CT clamp; you can combine up to three onto one transmitter (read on).

Just so it's clear: You'll need one transmitter plus two clamps initially, for your mains. Past that, each additional transmitter can monitor up to three circuit-breaker circuits (or even more). That's how I am monitoring 24 circuits (circuit breakers) with 10 transmitters.

What is all this?

Our breaker box. Click on the image three times for very high res. Also, most images have much more info if clicked.

You will need to put the clamps around hot (positive) wires in your circuit-breaker box. Of course, BE VERY CAREFUL. But if you or a friend knows a little about electricity, and is very careful, it's quite simple. Almost everything - but not completely everything! - inside your breaker box has insulation around it.

You don't need to re-wire anything; you don't need to cut any wires or put these in-line. No, you just need to put the little clamps around circuit-breaker leads you want to monitor, just like with clothespins. That's it!

In a sense, it's that simple. That said,

You will need to take the cover off of your breaker box. Once everything is working, you can put the cover back on, as long as the little wires from the clamps can run out to the transmitters. (You can't have the transmitters inside the box.) All of this shouldn't be a problem; they can run out from beneath the cover, if you don't screw it back on tight. Unless you have some very cramped/ ancient/ whatever breaker box.There is 24" inches of wire between the clamp and the plug for the transmitter.

Some circuit-breaker boxes, especially in old houses and probably apartments, may be quite small. You must have some room within your box to put these clamps. The regular (non-XL) clamps measure 56 mm x 32 mm x 20 mm, a slightly thick box of Tic-Tacs. It may not sound big, but boxes aren't made to house extras. I had some tortured convolutions (while trying to be super careful) to get my 19 Regular clamps on. This doesn't count the two slightly larger XL clamps for your mains - there's usually room around your mains. (And if there isn't room enough for two mains clamps, you can probably forget all the rest.)

What the flux? by Khyzyl Saleem

The CT clamps plug into the supplied transmitter. The transmitters accept up to three inputs, which is to say, one transmitter can monitor up to three of your circuit breakers.

Many people - most - probably only have the most basic Efergy setup: two CT clamps on their mains, one transmitter, and one hub, and are only monitoring their total house energy. But every additional transmitter can monitor up to three circuits.

Each hub can monitor up to 5 transmitters (more on this below).

If you want to go all-in, like I did, 10 transmitters (2 hubs) was enough to monitor almost every circuit in my 3600 sq.ft. house.
Our breaker box has 24 circuits (25 counting the overall mains). I did intelligent combining such as:

We have two HVACs (upper and lower), each of which actually uses three circuits (one for blower/furnace, two for external A/Cs). Putting the three circuits for each system on one transmitter shows everything going on for each HVAC on one transmitter. Said another way, one transmitter is for all the upper HVAC components, another is for all the lower HVAC components. We use natural gas, so in the winter, you see only the HVAC blower fan, but in the summer, you see the HVAC fan plus A/C condenser.

Several kitchen circuits on are one transmitter (our Siemens HG2415UC/02 range is gas but has supplementary 110V heater elements which shows signature spikes when the oven is first used),

The laundry (washer and dryer) are on one (you never use them simultaneously),

The relatively unused spare bedrooms and dining room (three circuits) are on one,

Efergy transmitters below dat box

And even clever wrinkles like

The master-bedroom/bath uses two circuits. Okay, good enough. Then I used the third jack on this transmitter to add the dishwasher. There's usually nothing going on in the MBR when we use the dishwasher. Many circuits are fairly chaotic, but in this particular case, it's easy to separate MBR activity (active at night) from dishwasher (day).

So the ten transmitters are logical functional groups that pretty much cover our whole house.

A closer look at the Efergy units

We don't need no steenkin' batteries

Setup is quite easy; follow the tutorials and instructions. They have made a good product in this respect. If you have any trouble, contact Efergy. The USA rep was great relative to purchases. But Efergy would not help with deeper answers (how they work); see below.

The CT clamps

These come in two sizes, the XL jacks for 200 amps ($16.25 each) and regular jacks for 100 amps ($11.25).

Unfortunately, their website has no stats on the sensitivity of each. In particular, I think I should have used regular jacks for everything, even the mains. It's sort of hard to think my house would use 200 A x 110 V = 22 kW on one branch of the main (44 kW on both). When both A/Cs are on, plus the usual amount of other stuff, I use ~4100 Watts. I can't help but think that measuring instruments should be matched to what they measure. Maybe some day on a lark, I will put regular clamps on the mains while keeping the XL ones there, and see what the results are.

One UPS to power them all

If you're wondering which CT clamps to get, you can draw very rough boundaries by looking at your single highest monthly electricity bill. It's a very poor estimate of instantaneous peak because it's only an average, but it will still give you some kind of ballpark. Unless you need 1.21 GW.

Or better yet, watch your meter when all your major devices are on... take a before, during, and after reading. Does it come anywhere near FORTY FOUR THOUSAND WATTS? I doubt it. Unless you are the person running DisneyWorld.

To make a long story short, I think most people should get regular jacks, even if they're only getting the base package for their mains (1 hub + 1 transmitter + 2 jacks). Talk to your Efergy rep when ordering and they should be happy to change it up.

I have no actual underlying EE (electrical engineer) reason for saying this with certainty. But it makes "walking around sense" to me.

The transmitters

Watts going on, hubs! click through for much more info

These little guys are wired to the CT clamps by a 2' wire. They use three AA batteries, or you can rig them with USB (below).

The transmitters send a signal every 10, 15, or 20 seconds (U.S.) or 6, 12, and 18 seconds (overseas). I have mine set to the lowest time (10 seconds), why not.

The Engage hub

They need to be in RF range of your transmitters, which is not a big problem. (But more on problems, below.)

They need a hardwire LAN connection. It looks like these units were first released June 2012. Things were more hard-LAN oriented back then, or at least, it simplifies the design.

As for specs, the hub has a LAN port and a power port, and three lights:

A red one for power (on when powered)

A yellow one (flickers as transmissions are received)

A green one for LAN (on when connected to router)

Its 5 V adapter is rated for 1.5 W and usually draws about 1.1 watts (see hubs closeup picture).

Efergy Graphs

Here's an example of my two graphs. Each hub only allows for 5 transmitters at most, so for 10 transmitters, I have two hubs and therefore two graphs (A and B). Because each transmitter allows up to three CT clamps, I could easily group my 24 breakers into these 10 transmitters (graph lines) to see everything going on in my house. Actually A1 is the mains, so it's nine functional groups.

My Hub A for July 19, 2017. The Mains (total power) is in red, plus our two HVACs and two other circuit-breaker groups. Click on the pic to see much more info on what's being presented.

My Hub B for July 19, 2017 with the rest of my functional electrical groups. Click on the pic to see much more info on what's being presented.

Zoom on the Hub A pic above, for 10:30 pm to midnight. You can easily scroll or zoom on Efergy graphs however you like. For the hardcore, there are some serious limitations to this ability (see below).

Closeup on Hub B, midnight to 4 pm. Notice the frig cycling, and the time I got online. Click on the pic for more info.